Laserfiche WebLink
Residual Contamination;Future Effects <br /> Since the tanks and piping sere removed and backfill <br /> material was excavated, potential sources for further <br /> contamination no longer exist. The low contaminant <br /> concentrations remaining in soil and the low permeabil.it,r <br /> soil observed in the soil borings constitute adequate <br /> protection from contamination of additional soils or <br /> degradation of groundwater quality or beneficial uses. The <br /> concentrations of residuals in soils are well bslow <br /> de-,ignated levels to protect groundwater as specified in <br /> "Water Quality Goals, Hazardous Criteria, and Designated <br /> Level Examples for Chemical Zonstituerts, " by the California <br /> Regional 'dater Quality :,ontrol Board, Central Valley Region. <br /> The "designated levels" utilize attenuation factors assigned �5 <br /> for conditions at a hypothetical average site. Higher or <br /> lower factors could be considered if warranted by site <br /> specific conditions such a depth to groundwater, sola <br /> caaracteristics, contaminant, and contaminant concentration. <br /> "Average site" attenuation factors are appropriate for <br /> application at the suoject site given sits characteristics <br /> i e depth to groundwater greater than 43 feetk, substantial <br /> fine-drained, low-per eability soils encountered between <br /> conta.iinant source and groundwater. <br /> 3 3 additional Measures <br /> Due to the low contaminant levels observed, drill cuttings <br /> which are currently stockpiled on-site, approximately one <br /> cubic yard, should oe disposed at a c_ass I! landfill, or <br /> . ot:ner appropriate disposal site. vo further subsurface <br /> investigative measures are proposed. <br /> a <br />